1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2014 Ezequiel Garcia
4 * Copyright (c) 2011 Free Electrons
5 *
6 * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
7 * Copyright (c) International Business Machines Corp., 2006
8 * Copyright (c) Nokia Corporation, 2007
9 * Authors: Artem Bityutskiy, Frank Haverkamp
10 */
11
12/*
13 * Read-only block devices on top of UBI volumes
14 *
15 * A simple implementation to allow a block device to be layered on top of a
16 * UBI volume. The implementation is provided by creating a static 1-to-1
17 * mapping between the block device and the UBI volume.
18 *
19 * The addressed byte is obtained from the addressed block sector, which is
20 * mapped linearly into the corresponding LEB:
21 *
22 * LEB number = addressed byte / LEB size
23 *
24 * This feature is compiled in the UBI core, and adds a 'block' parameter
25 * to allow early creation of block devices on top of UBI volumes. Runtime
26 * block creation/removal for UBI volumes is provided through two UBI ioctls:
27 * UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
28 */
29
30#include <linux/module.h>
31#include <linux/init.h>
32#include <linux/err.h>
33#include <linux/kernel.h>
34#include <linux/list.h>
35#include <linux/mutex.h>
36#include <linux/slab.h>
37#include <linux/mtd/ubi.h>
38#include <linux/blkdev.h>
39#include <linux/blk-mq.h>
40#include <linux/hdreg.h>
41#include <linux/scatterlist.h>
42#include <linux/idr.h>
43#include <asm/div64.h>
44
45#include "ubi-media.h"
46#include "ubi.h"
47
48/* Maximum number of supported devices */
49#define UBIBLOCK_MAX_DEVICES 32
50
51/* Maximum length of the 'block=' parameter */
52#define UBIBLOCK_PARAM_LEN 63
53
54/* Maximum number of comma-separated items in the 'block=' parameter */
55#define UBIBLOCK_PARAM_COUNT 2
56
57struct ubiblock_param {
58 int ubi_num;
59 int vol_id;
60 char name[UBIBLOCK_PARAM_LEN+1];
61};
62
63struct ubiblock_pdu {
64 struct ubi_sgl usgl;
65};
66
67/* Numbers of elements set in the @ubiblock_param array */
68static int ubiblock_devs;
69
70/* MTD devices specification parameters */
71static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES];
72
73struct ubiblock {
74 struct ubi_volume_desc *desc;
75 int ubi_num;
76 int vol_id;
77 int refcnt;
78 int leb_size;
79
80 struct gendisk *gd;
81 struct request_queue *rq;
82
83 struct mutex dev_mutex;
84 struct list_head list;
85 struct blk_mq_tag_set tag_set;
86};
87
88/* Linked list of all ubiblock instances */
89static LIST_HEAD(ubiblock_devices);
90static DEFINE_IDR(ubiblock_minor_idr);
91/* Protects ubiblock_devices and ubiblock_minor_idr */
92static DEFINE_MUTEX(devices_mutex);
93static int ubiblock_major;
94
95static int __init ubiblock_set_param(const char *val,
96 const struct kernel_param *kp)
97{
98 int i, ret;
99 size_t len;
100 struct ubiblock_param *param;
101 char buf[UBIBLOCK_PARAM_LEN];
102 char *pbuf = &buf[0];
103 char *tokens[UBIBLOCK_PARAM_COUNT];
104
105 if (!val)
106 return -EINVAL;
107
108 len = strnlen(p: val, UBIBLOCK_PARAM_LEN);
109 if (len == 0) {
110 pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
111 return 0;
112 }
113
114 if (len == UBIBLOCK_PARAM_LEN) {
115 pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
116 val, UBIBLOCK_PARAM_LEN);
117 return -EINVAL;
118 }
119
120 strcpy(p: buf, q: val);
121
122 /* Get rid of the final newline */
123 if (buf[len - 1] == '\n')
124 buf[len - 1] = '\0';
125
126 for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
127 tokens[i] = strsep(&pbuf, ",");
128
129 param = &ubiblock_param[ubiblock_devs];
130 if (tokens[1]) {
131 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
132 ret = kstrtoint(s: tokens[0], base: 10, res: &param->ubi_num);
133 if (ret < 0)
134 return -EINVAL;
135
136 /* Second param can be a number or a name */
137 ret = kstrtoint(s: tokens[1], base: 10, res: &param->vol_id);
138 if (ret < 0) {
139 param->vol_id = -1;
140 strcpy(p: param->name, q: tokens[1]);
141 }
142
143 } else {
144 /* One parameter: must be device path */
145 strcpy(p: param->name, q: tokens[0]);
146 param->ubi_num = -1;
147 param->vol_id = -1;
148 }
149
150 ubiblock_devs++;
151
152 return 0;
153}
154
155static const struct kernel_param_ops ubiblock_param_ops = {
156 .set = ubiblock_set_param,
157};
158module_param_cb(block, &ubiblock_param_ops, NULL, 0);
159MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
160 "Multiple \"block\" parameters may be specified.\n"
161 "UBI volumes may be specified by their number, name, or path to the device node.\n"
162 "Examples\n"
163 "Using the UBI volume path:\n"
164 "ubi.block=/dev/ubi0_0\n"
165 "Using the UBI device, and the volume name:\n"
166 "ubi.block=0,rootfs\n"
167 "Using both UBI device number and UBI volume number:\n"
168 "ubi.block=0,0\n");
169
170static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
171{
172 struct ubiblock *dev;
173
174 list_for_each_entry(dev, &ubiblock_devices, list)
175 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
176 return dev;
177 return NULL;
178}
179
180static blk_status_t ubiblock_read(struct request *req)
181{
182 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(rq: req);
183 struct ubiblock *dev = req->q->queuedata;
184 u64 pos = blk_rq_pos(rq: req) << 9;
185 int to_read = blk_rq_bytes(rq: req);
186 int bytes_left = to_read;
187 /* Get LEB:offset address to read from */
188 int offset = do_div(pos, dev->leb_size);
189 int leb = pos;
190 struct req_iterator iter;
191 struct bio_vec bvec;
192 int ret;
193
194 blk_mq_start_request(rq: req);
195
196 /*
197 * It is safe to ignore the return value of blk_rq_map_sg() because
198 * the number of sg entries is limited to UBI_MAX_SG_COUNT
199 * and ubi_read_sg() will check that limit.
200 */
201 ubi_sgl_init(usgl: &pdu->usgl);
202 blk_rq_map_sg(q: req->q, rq: req, sglist: pdu->usgl.sg);
203
204 while (bytes_left) {
205 /*
206 * We can only read one LEB at a time. Therefore if the read
207 * length is larger than one LEB size, we split the operation.
208 */
209 if (offset + to_read > dev->leb_size)
210 to_read = dev->leb_size - offset;
211
212 ret = ubi_read_sg(desc: dev->desc, lnum: leb, sgl: &pdu->usgl, offset, len: to_read);
213 if (ret < 0)
214 break;
215
216 bytes_left -= to_read;
217 to_read = bytes_left;
218 leb += 1;
219 offset = 0;
220 }
221
222 rq_for_each_segment(bvec, req, iter)
223 flush_dcache_page(page: bvec.bv_page);
224
225 blk_mq_end_request(rq: req, error: errno_to_blk_status(errno: ret));
226
227 return BLK_STS_OK;
228}
229
230static int ubiblock_open(struct gendisk *disk, blk_mode_t mode)
231{
232 struct ubiblock *dev = disk->private_data;
233 int ret;
234
235 mutex_lock(&dev->dev_mutex);
236 if (dev->refcnt > 0) {
237 /*
238 * The volume is already open, just increase the reference
239 * counter.
240 */
241 goto out_done;
242 }
243
244 /*
245 * We want users to be aware they should only mount us as read-only.
246 * It's just a paranoid check, as write requests will get rejected
247 * in any case.
248 */
249 if (mode & BLK_OPEN_WRITE) {
250 ret = -EROFS;
251 goto out_unlock;
252 }
253 dev->desc = ubi_open_volume(ubi_num: dev->ubi_num, vol_id: dev->vol_id, mode: UBI_READONLY);
254 if (IS_ERR(ptr: dev->desc)) {
255 dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
256 dev->ubi_num, dev->vol_id);
257 ret = PTR_ERR(ptr: dev->desc);
258 dev->desc = NULL;
259 goto out_unlock;
260 }
261
262out_done:
263 dev->refcnt++;
264 mutex_unlock(lock: &dev->dev_mutex);
265 return 0;
266
267out_unlock:
268 mutex_unlock(lock: &dev->dev_mutex);
269 return ret;
270}
271
272static void ubiblock_release(struct gendisk *gd)
273{
274 struct ubiblock *dev = gd->private_data;
275
276 mutex_lock(&dev->dev_mutex);
277 dev->refcnt--;
278 if (dev->refcnt == 0) {
279 ubi_close_volume(desc: dev->desc);
280 dev->desc = NULL;
281 }
282 mutex_unlock(lock: &dev->dev_mutex);
283}
284
285static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
286{
287 /* Some tools might require this information */
288 geo->heads = 1;
289 geo->cylinders = 1;
290 geo->sectors = get_capacity(disk: bdev->bd_disk);
291 geo->start = 0;
292 return 0;
293}
294
295static const struct block_device_operations ubiblock_ops = {
296 .owner = THIS_MODULE,
297 .open = ubiblock_open,
298 .release = ubiblock_release,
299 .getgeo = ubiblock_getgeo,
300};
301
302static blk_status_t ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
303 const struct blk_mq_queue_data *bd)
304{
305 switch (req_op(req: bd->rq)) {
306 case REQ_OP_READ:
307 return ubiblock_read(req: bd->rq);
308 default:
309 return BLK_STS_IOERR;
310 }
311}
312
313static int ubiblock_init_request(struct blk_mq_tag_set *set,
314 struct request *req, unsigned int hctx_idx,
315 unsigned int numa_node)
316{
317 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(rq: req);
318
319 sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
320 return 0;
321}
322
323static const struct blk_mq_ops ubiblock_mq_ops = {
324 .queue_rq = ubiblock_queue_rq,
325 .init_request = ubiblock_init_request,
326};
327
328static int calc_disk_capacity(struct ubi_volume_info *vi, u64 *disk_capacity)
329{
330 u64 size = vi->used_bytes >> 9;
331
332 if (vi->used_bytes % 512) {
333 if (vi->vol_type == UBI_DYNAMIC_VOLUME)
334 pr_warn("UBI: block: volume size is not a multiple of 512, last %llu bytes are ignored!\n",
335 vi->used_bytes - (size << 9));
336 else
337 pr_info("UBI: block: volume size is not a multiple of 512, last %llu bytes are ignored!\n",
338 vi->used_bytes - (size << 9));
339 }
340
341 if ((sector_t)size != size)
342 return -EFBIG;
343
344 *disk_capacity = size;
345
346 return 0;
347}
348
349int ubiblock_create(struct ubi_volume_info *vi)
350{
351 struct queue_limits lim = {
352 .max_segments = UBI_MAX_SG_COUNT,
353 };
354 struct ubiblock *dev;
355 struct gendisk *gd;
356 u64 disk_capacity;
357 int ret;
358
359 ret = calc_disk_capacity(vi, disk_capacity: &disk_capacity);
360 if (ret) {
361 return ret;
362 }
363
364 /* Check that the volume isn't already handled */
365 mutex_lock(&devices_mutex);
366 if (find_dev_nolock(ubi_num: vi->ubi_num, vol_id: vi->vol_id)) {
367 ret = -EEXIST;
368 goto out_unlock;
369 }
370
371 dev = kzalloc(size: sizeof(struct ubiblock), GFP_KERNEL);
372 if (!dev) {
373 ret = -ENOMEM;
374 goto out_unlock;
375 }
376
377 mutex_init(&dev->dev_mutex);
378
379 dev->ubi_num = vi->ubi_num;
380 dev->vol_id = vi->vol_id;
381 dev->leb_size = vi->usable_leb_size;
382
383 dev->tag_set.ops = &ubiblock_mq_ops;
384 dev->tag_set.queue_depth = 64;
385 dev->tag_set.numa_node = NUMA_NO_NODE;
386 dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING;
387 dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
388 dev->tag_set.driver_data = dev;
389 dev->tag_set.nr_hw_queues = 1;
390
391 ret = blk_mq_alloc_tag_set(set: &dev->tag_set);
392 if (ret) {
393 dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
394 goto out_free_dev;
395 }
396
397
398 /* Initialize the gendisk of this ubiblock device */
399 gd = blk_mq_alloc_disk(&dev->tag_set, &lim, dev);
400 if (IS_ERR(ptr: gd)) {
401 ret = PTR_ERR(ptr: gd);
402 goto out_free_tags;
403 }
404
405 gd->fops = &ubiblock_ops;
406 gd->major = ubiblock_major;
407 gd->minors = 1;
408 gd->first_minor = idr_alloc(&ubiblock_minor_idr, ptr: dev, start: 0, end: 0, GFP_KERNEL);
409 if (gd->first_minor < 0) {
410 dev_err(disk_to_dev(gd),
411 "block: dynamic minor allocation failed");
412 ret = -ENODEV;
413 goto out_cleanup_disk;
414 }
415 gd->flags |= GENHD_FL_NO_PART;
416 gd->private_data = dev;
417 sprintf(buf: gd->disk_name, fmt: "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
418 set_capacity(disk: gd, size: disk_capacity);
419 dev->gd = gd;
420
421 dev->rq = gd->queue;
422
423 list_add_tail(new: &dev->list, head: &ubiblock_devices);
424
425 /* Must be the last step: anyone can call file ops from now on */
426 ret = device_add_disk(parent: vi->dev, disk: dev->gd, NULL);
427 if (ret)
428 goto out_remove_minor;
429
430 dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
431 dev->ubi_num, dev->vol_id, vi->name);
432 mutex_unlock(lock: &devices_mutex);
433 return 0;
434
435out_remove_minor:
436 list_del(entry: &dev->list);
437 idr_remove(&ubiblock_minor_idr, id: gd->first_minor);
438out_cleanup_disk:
439 put_disk(disk: gd);
440out_free_tags:
441 blk_mq_free_tag_set(set: &dev->tag_set);
442out_free_dev:
443 kfree(objp: dev);
444out_unlock:
445 mutex_unlock(lock: &devices_mutex);
446
447 return ret;
448}
449
450static void ubiblock_cleanup(struct ubiblock *dev)
451{
452 int id = dev->gd->first_minor;
453
454 /* Stop new requests to arrive */
455 del_gendisk(gp: dev->gd);
456 /* Finally destroy the blk queue */
457 dev_info(disk_to_dev(dev->gd), "released");
458 put_disk(disk: dev->gd);
459 blk_mq_free_tag_set(set: &dev->tag_set);
460 idr_remove(&ubiblock_minor_idr, id);
461}
462
463int ubiblock_remove(struct ubi_volume_info *vi)
464{
465 struct ubiblock *dev;
466 int ret;
467
468 mutex_lock(&devices_mutex);
469 dev = find_dev_nolock(ubi_num: vi->ubi_num, vol_id: vi->vol_id);
470 if (!dev) {
471 ret = -ENODEV;
472 goto out_unlock;
473 }
474
475 /* Found a device, let's lock it so we can check if it's busy */
476 mutex_lock(&dev->dev_mutex);
477 if (dev->refcnt > 0) {
478 ret = -EBUSY;
479 goto out_unlock_dev;
480 }
481
482 /* Remove from device list */
483 list_del(entry: &dev->list);
484 ubiblock_cleanup(dev);
485 mutex_unlock(lock: &dev->dev_mutex);
486 mutex_unlock(lock: &devices_mutex);
487
488 kfree(objp: dev);
489 return 0;
490
491out_unlock_dev:
492 mutex_unlock(lock: &dev->dev_mutex);
493out_unlock:
494 mutex_unlock(lock: &devices_mutex);
495 return ret;
496}
497
498static int ubiblock_resize(struct ubi_volume_info *vi)
499{
500 struct ubiblock *dev;
501 u64 disk_capacity;
502 int ret;
503
504 /*
505 * Need to lock the device list until we stop using the device,
506 * otherwise the device struct might get released in
507 * 'ubiblock_remove()'.
508 */
509 mutex_lock(&devices_mutex);
510 dev = find_dev_nolock(ubi_num: vi->ubi_num, vol_id: vi->vol_id);
511 if (!dev) {
512 mutex_unlock(lock: &devices_mutex);
513 return -ENODEV;
514 }
515
516 ret = calc_disk_capacity(vi, disk_capacity: &disk_capacity);
517 if (ret) {
518 mutex_unlock(lock: &devices_mutex);
519 if (ret == -EFBIG) {
520 dev_warn(disk_to_dev(dev->gd),
521 "the volume is too big (%d LEBs), cannot resize",
522 vi->size);
523 }
524 return ret;
525 }
526
527 mutex_lock(&dev->dev_mutex);
528
529 if (get_capacity(disk: dev->gd) != disk_capacity) {
530 set_capacity(disk: dev->gd, size: disk_capacity);
531 dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
532 vi->used_bytes);
533 }
534 mutex_unlock(lock: &dev->dev_mutex);
535 mutex_unlock(lock: &devices_mutex);
536 return 0;
537}
538
539static bool
540match_volume_desc(struct ubi_volume_info *vi, const char *name, int ubi_num, int vol_id)
541{
542 int err, len, cur_ubi_num, cur_vol_id;
543
544 if (ubi_num == -1) {
545 /* No ubi num, name must be a vol device path */
546 err = ubi_get_num_by_path(pathname: name, ubi_num: &cur_ubi_num, vol_id: &cur_vol_id);
547 if (err || vi->ubi_num != cur_ubi_num || vi->vol_id != cur_vol_id)
548 return false;
549
550 return true;
551 }
552
553 if (vol_id == -1) {
554 /* Got ubi_num, but no vol_id, name must be volume name */
555 if (vi->ubi_num != ubi_num)
556 return false;
557
558 len = strnlen(p: name, UBI_VOL_NAME_MAX + 1);
559 if (len < 1 || vi->name_len != len)
560 return false;
561
562 if (strcmp(name, vi->name))
563 return false;
564
565 return true;
566 }
567
568 if (vi->ubi_num != ubi_num)
569 return false;
570
571 if (vi->vol_id != vol_id)
572 return false;
573
574 return true;
575}
576
577static void
578ubiblock_create_from_param(struct ubi_volume_info *vi)
579{
580 int i, ret = 0;
581 struct ubiblock_param *p;
582
583 /*
584 * Iterate over ubiblock cmdline parameters. If a parameter matches the
585 * newly added volume create the ubiblock device for it.
586 */
587 for (i = 0; i < ubiblock_devs; i++) {
588 p = &ubiblock_param[i];
589
590 if (!match_volume_desc(vi, name: p->name, ubi_num: p->ubi_num, vol_id: p->vol_id))
591 continue;
592
593 ret = ubiblock_create(vi);
594 if (ret) {
595 pr_err(
596 "UBI: block: can't add '%s' volume on ubi%d_%d, err=%d\n",
597 vi->name, p->ubi_num, p->vol_id, ret);
598 }
599 break;
600 }
601}
602
603static int ubiblock_notify(struct notifier_block *nb,
604 unsigned long notification_type, void *ns_ptr)
605{
606 struct ubi_notification *nt = ns_ptr;
607
608 switch (notification_type) {
609 case UBI_VOLUME_ADDED:
610 ubiblock_create_from_param(vi: &nt->vi);
611 break;
612 case UBI_VOLUME_REMOVED:
613 ubiblock_remove(vi: &nt->vi);
614 break;
615 case UBI_VOLUME_RESIZED:
616 ubiblock_resize(vi: &nt->vi);
617 break;
618 case UBI_VOLUME_UPDATED:
619 /*
620 * If the volume is static, a content update might mean the
621 * size (i.e. used_bytes) was also changed.
622 */
623 if (nt->vi.vol_type == UBI_STATIC_VOLUME)
624 ubiblock_resize(vi: &nt->vi);
625 break;
626 default:
627 break;
628 }
629 return NOTIFY_OK;
630}
631
632static struct notifier_block ubiblock_notifier = {
633 .notifier_call = ubiblock_notify,
634};
635
636static void ubiblock_remove_all(void)
637{
638 struct ubiblock *next;
639 struct ubiblock *dev;
640
641 mutex_lock(&devices_mutex);
642 list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
643 /* The module is being forcefully removed */
644 WARN_ON(dev->desc);
645 /* Remove from device list */
646 list_del(entry: &dev->list);
647 ubiblock_cleanup(dev);
648 kfree(objp: dev);
649 }
650 mutex_unlock(lock: &devices_mutex);
651}
652
653int __init ubiblock_init(void)
654{
655 int ret;
656
657 ubiblock_major = register_blkdev(0, "ubiblock");
658 if (ubiblock_major < 0)
659 return ubiblock_major;
660
661 ret = ubi_register_volume_notifier(nb: &ubiblock_notifier, ignore_existing: 0);
662 if (ret)
663 goto err_unreg;
664 return 0;
665
666err_unreg:
667 unregister_blkdev(major: ubiblock_major, name: "ubiblock");
668 ubiblock_remove_all();
669 return ret;
670}
671
672void __exit ubiblock_exit(void)
673{
674 ubi_unregister_volume_notifier(nb: &ubiblock_notifier);
675 ubiblock_remove_all();
676 unregister_blkdev(major: ubiblock_major, name: "ubiblock");
677}
678

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source code of linux/drivers/mtd/ubi/block.c